Joystick Control for Gearbox with Segmented Bowden Cables
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Solution Overview
Problem
Existing joysticks for remotely controlling gear selection in agricultural vehicles lack precision and feel, requiring short crisp movements and offering resistance only when needed, while being bulky and complex in construction.
Innovation Solution
A joystick control with a support body, rotatable axle, and actuating members connected by Bowden cables, allowing selective engagement of Bowden cables based on operating lever movement, enabling precise gear selection without transmitting side-to-side movement to the gearbox, using two selectors controlled independently by separate Bowden cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two Bowden cables are used to control both horizontal and vertical movement of the gear stick, then remote gear selection is achieved, but the structure becomes bulky and complicated
Solution Approach 1:
The invention divides the control function into two independent parts: one Bowden cable controls horizontal movement (selector engagement) and the other controls vertical movement (gear selection). This segmentation allows each cable to handle only one degree of freedom, simplifying the overall structure while maintaining remote control capability.
Solution Approach 2:
The patent introduces an intermediary mechanical linkage system consisting of the operating lever, pivot pin, and axle assembly. This intermediary mechanism translates the operator's lever movements into corresponding cable tensions, providing precise control while isolating the cable system from direct mechanical complexity.
2Ease of operation
If the operating lever is connected to control both horizontal and vertical gear stick movement, then gear selection is achieved, but the lever lacks precise control and proper feel
Solution Approach 1:
By separating the control functions into two independent Bowden cables, each cable provides precise control over its specific degree of freedom without interference from the other direction's movements, enhancing overall control precision.
Solution Approach 2:
The invention applies different control characteristics to different directions: horizontal movement provides crisp selector engagement feel, while vertical movement provides smooth gear selection. Each direction is optimized independently through dedicated cable control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The joystick provides precise control with clear resistance cues, reducing bulkiness and complexity by isolating side-to-side movement, allowing crisp and precise gear changes with improved user feedback.
Implementation Method 1
One of the cables ensures that the gear stick is moved horizontally to engage the appropriate selector as the operating lever on the joystick is moved from side to side and the other moves the gear stick up and down to select the desired speed as the operating lever of the joystick is moved up and down
Data Source
Figure 1~3
Figure 4
AI summary
A joystick control is disclosed for a change speed gearbox in which two selector are separately controllable remotely. The joystick control comprises a support body (12), an axle (18) rotatably supported by the body (12), and an operating lever (24) connected to the axle by a pivot pin (26) such that the operating lever (24) is rotatable about the axis of the axle (18) in one plane and is pivotable relative to the axle (18) about the axis of the pivot pin (26) in an orthogonal plane. Two actuating members (30) are rotatably supported by the axle (18) and arranged one on each side of the operating lever (18). Each actuating member (30) is connectible by a respective Bowden cable to one of the selectors of the gearbox and extends and retracts the cable in response to rotation of the actuating member (30) about the axle (18). Mating formations (24a) and (50) on the operating lever (24) and the actuating members (30) allow the operating lever (24) to be engaged selectively for rotation with one or the other of the actuating members (30) in dependence upon the direction in which the operating lever (30) is pivoted relative to the axle (18) about the pivot pin (26).